This invention relates to an improved puller for the removal of parts which may be jam fitted to shafts, housings and the like. In a preferred embodiment the improved puller is particularly suitable for the removal of flexible impellers from a shaft of a water pump.
Many mechanical assemblies generally comprise a housing wherein a shaft has a jam or otherwise closely fitted race, bearing, impeller or the like which is mounted to rotate with the shaft. Typically the removal of such components from the shaft for repair or replacement is problematic and requires use of a puller or the like tool.
Many mechanical assemblies comprise centrifugal pumps which generally comprise an impeller closely fitted on a shaft, the impeller being inserted within a housing, the arrangement being designed to pump liquids. For example, liquid cooled internal combustion engines are commonly designed to incorporate water pumps as an integral part of the engine and/or drive train. In marine engine embodiments, the water pump generally comprises a flexible impeller of varying size, dimensions and number of blades. The impeller generally comprises a plurality of resilient, generally elastomeric, curved arms/blades arranged spaced as spokes bonded around a metal hub, the hub having a central opening for mounting to a shaft which rotates the impeller.
It is not unusual for such impellers to be removed for replacement and/or repair, with removal being generally time consuming because of the close tolerance positioning of the water pump on the motor, the close positioning of the motor in the vehicle and/or boat, the jam fit by which the hub of the impeller is typically mounted to a water pump shaft and/or the effects of corrosion, dirt and the like among the shaft and the impeller. It is not unusual for a technician to be forced to use a pair of flat screw drivers to slowly pry the impeller from the shaft, creating the danger of damage to the housing and in many instances so damaging the impeller and/or housing as to make it non-repairable, non-rebuildable or even non-reusable once removed.
Various pullers have been proposed for use in removal of components from their supporting shaft but each have limitations in use. U.S. Pat. No. 5,341,553 discloses puller particularly suitable for pulling impellers from water pumps of marine engines, which purports to solve the problem of flexible impeller removal from water pump shafts, but has been found problematic in that it is easily misaligned and can cause damage to the impeller and even further jam the impeller on the shaft and make the removal process more difficult and even technically elusive to a technician.
U.S. Pat. No. 5,983,474 discloses an improved puller to that disclosed in U.S. Pat. No. 5,341,553, the improved puller having a wider breadth of efficient uses including being more efficient in removing an impeller by automatically aligning and significantly reducing damage to the impeller during removal. Unfortunately, the device is expensive to manufacture and thus has limited buyer appeal to those primarily seeking a low cost impeller removal device.
It is an object of the present invention to provide an improved puller which will facilitate the removal of components from shafts, particularly impellers.
It is another object of the invention to provide a universal impeller puller which is easily aligned and convenient to operate for the effective removal of a flexible impeller from a pump housing.
It is a still further object of the invention to provide a universal impeller puller which is cost effective to manufacture.
These and other objects of the invention will become apparent in the following recitation of the invention.
The present invention comprises an improved adjustable puller which has particular application for uses disclosed in U.S. Pat. No. 5,341,553 in the removal of flexible impellers of spaced blade design having varying dimension and number of blades.
The improved adjustable puller generally comprises an elongate support member having a first and opposite end. The support member comprises spaced apart first and second gripping jaw members, arranged to extend radially outwardly, in generally alignment to each other, from the support member to engage a hub of an impeller, and an elongate, twist threaded extraction screw member, which is arranged to be incrementally screwed radially outwardly from the support member in general alignment with said jaw members to engage a hub mounting shaft and force extraction of the hub, and thus the impeller, from the shaft.
In the arrangement of the invention, the first jaw member is arranged proximate the first end of the elongate support member, the second jaw member is slidably mounted along the support member arranged for variably spaced movement thereof toward and away from the first jaw member, and the elongate extraction screw member is mounted to the support member between the jaw members or between the first jaw member and about the first end of the support member.
In one embodiment, the first jaw member is arranged spaced proximate to the first end of the support member, and the elongate extraction screw member is mounted along the support member between the first jaw member and at or about the first end of the support member. In a preferred embodiment the extraction screw member is slidably mounted between the first jaw member and the first end.
In another embodiment, the first jaw member is arranged near proximate the first end of the support member, and the elongate extraction screw member is slidably mounted along the support member between the first jaw member and the second jaw member.
In a pivot plier embodiment, the support member comprises first and second elongate members, the first jaw member is integral to the first elongate member, being either directly cast or otherwise fixed thereto with the elongate length of the first elongate member extending about perpendicular from the first jaw member as an elongate handle. The first elongate member comprises a plurality of about equal diameter holes which overlap at their circumference so as to create an opening therebetween. The holes are spaced from the first jaw member and are aligned along the support member in spaced gradient therefrom. The second jaw member is integral or otherwise fixed to a second elongate member. The second elongate member comprises a stud extending in a plane about perpendicular to the second jaw member and spaced therefrom. The stud is sized to extend from the second member and couple with the overlapping holes of the first member. Slidable movement of the stud through the openings formed by the overlapping arrangement, enables movement of the stud from hole to hole. The arrangement enables slidably moving the stud and thus the second jaw member from hole to overlapping hole along the support member without removal of the stud from the plurality of holes. Such coupled arrangement of gripping jaws and handles is generally referred to as a pivot plier type arrangement.
In operation of the pivot plier embodiment, the second jaw member is moved from hole to hole as desired to position the second jaw member along the support member in a desired spaced relationship to the first jaw member. The extended length of the elongate members comprise handles, arranged to be generally offset angled from each other at all spaced hole positions and hand compressing the handles toward each other causes the second jaw member to pivot at the coupled position of stud and hole, and grip the hub of the impeller between the jaws. In one arrangement of this embodiment, the holes are sized and arranged to provide spacing between the jaws, when in a generally parallel opposing position, which corresponds to standard diameters of hubs of standard impellers. In a particularly preferred embodiment, the first jaw is angled from perpendicular toward the second jaw to provide first gripping pressure by the jaw on the interior end of the hub.
In such pivot plier embodiment the elongate extraction screw member can be arranged slidable between the jaw members or between the first jaw member and the first end of the support member. Thus, in an arrangement wherein the elongate extraction screw member is slidably mounted to the support member between the first jaw member and the second jaw member, the opposing jaws of the device are aligned on the exterior surface of the hub and the handles pressed together to secure the device to the hub. The elongate extraction screw member is moved to a position adjacent the end of the shaft mounting the hub and is twist screwed to directly engage the shaft and disengage the hub from the shaft, with the handles extending outwardly generally perpendicular to the centerline of the shaft to be used as a lever so that the hub can be coincidentally rocked from side to side for assisting extraction of the impeller.
In a pivot plier arrangement wherein the elongate extraction screw member is mounted to the support member between the first jaw member and the first end of the support member, the opposing jaws of the device are aligned on the exterior surface at opposite points on the hub and the handles pressed toward each other to secure the device to the hub as described aforesaid, and the elongate extraction screw member is positioned to engage the housing, with the outwardly extending handles used to leverage a prying extraction action to pull the impeller from the shaft.
Generally, such pivot plier arrangement relies upon the user maintaining a significant force upon both handles to retain the grip of the jaws upon the hub of the impeller. In a preferred embodiment, means are provided whereupon the handles can be retained at a desired force by a locking loop, latch and the like which enables the user to release the handles while pivot plier retains the desired grip on the hub.
In a twist screw urged embodiment of the invention, a jaw member, slidably mounted along the elongate support member, is arranged to be twist screw urged toward the other jaw member as distinct from manual pivot levered urging of offset handles. As with the pivot plier embodiment, it is preferred that a first jaw member be fixed proximate the first end of the support member and generally about perpendicular thereto. The second jaw member is slidably mounted along the support member and a twist screw urging means is arranged generally along a longitudinal axis of the support member so as to engage the second jaw member and urge it toward the first jaw member.
In one twist screw urged embodiment, the support member comprises an elongate slotted hollow tube in which an integral base end of the jaw member is slidably retained and the twist screw urging member is arranged so than an end thereof engages the base end of the jaw member for urging same toward the other jaw member. Generally, any convenient tube can be adopted for this embodiment, but preferably a polygonal walled tube and most preferably four walled box tube construction is preferred.
In a particularly convenient twist screw urged assembly of the invention, the support member is a constructed four wall box tube formed by connecting two elongate generally xe2x80x9cUxe2x80x9d shaped channel members, spaced apart with legs facing, in generally parallel facing opposition. The jaw members comprise an enlarged base which has extending therefrom a narrowed elongate toothed jaw. The base end of the jaw member is generally polygonal configured and is sized to fit between the legs of the facing channels, with the elongate toothed end being sufficiently narrow to extend through the opening between the spaced apart channel members. The base end of the first jaw member is sized and configured to be a spacer block, to which the facing channel members can be connected to retain their spaced relationship at a first end of the support member. A similarly dimensioned polygonal configured spacer urging block is arranged to connect the facing channel members in spaced relationship at about the opposite end of the support member. The spacer urging block comprises a threaded hole therethrough along about a central axis of the constructed support member for threaded insertion of a mating twist threaded urging screw member. Thus, the channel members are connected to the spacer blocks to form a four walled elongate tube support member having a generally polygonal interior hollow between the spacer blocks and containing aligned elongate slotted openings through opposite surfaces of the support member surrounding the hollow.
The polygonal configured base end of the second jaw member is dimensioned slightly smaller than the polygonal configured spacer urging block and base end of the first jaw member and is arranged within the hollow, with the narrowed elongate toothed jaw extending through the slot in general alignment with the elongate toothed jaw end of the first jaw member. The slightly smaller dimensioning of the base end of the second jaw member enables it to be slidably moved longitudinally within the hollow of the support member.
Arranged within the hollow between the first and second jaw member, is an extraction screw means comprising a polygonal extraction block having a threaded hole there-through, this hole being arranged in the hollow about perpendicular to a longitudinal axis of the support member. As with the second jaw member, the extraction block is sized and dimensioned slightly smaller than the polygonal configured spacer urging block and base end of the first jaw member so as to slidably move longitudinally within the hollow of the support member. The threaded hole in the extraction block is dimensioned such that a mating twist threaded extraction screw member can be threaded through the block without interference with the sides of the aligned elongate slotted openings formed by the channel members comprising the support member.
This assembly is not only particularly convenient to assemble, but enables a locking grip to be maintained by the jaws on the hub and by providing an appropriate configured surface on the urging screw member, enables the use of a wrench or other leveraged tool for urging the jaws against the hub. As with the pivot plier arrangement, the opposite end of the elongate support member may be used for leverage rocking of the hub off the shaft, and an extraction screw member may even be positioned proximate the first end of the support member to enable leveraged prying of the hub off the shaft.
The gripping jaw members generally comprise an elongate structure, having one or more gripping elements arranged along the surface thereof which faces the hub of the impeller. In a preferred embodiment, gripping elements are arranged along its length as teeth extending from the surface.
A typical impeller for pumping water in motorized water craft, comprises a plurality of elastomer arms integrally bonded to a metallic hub. The impeller sits within a closely confining space, the hub generally sized to have a close axial clearance from the front and back of the housing. Generally the clearance is so close within the interior space of the housing, that teeth of the gripping jaws cannot be arranged to engage the rear edge of the hub, and in order for the puller to gain a suitable grip, the teeth must engage the elastomer bonding on the hub. Thus, the gripping elements of the gripping jaws engage the elastomer bonded to the hub, the extraction screw member engages the shaft and as the support member is forced axially outwardly from the shaft, the gripping jaws pull the hub axially along with it.
In a preferred embodiment, the end of the jaw members are angled toward each other so that the force generated by the extraction screw member is concentrated at the interior end of the hub significantly reducing the likelihood of tearing the elastomeric covering from the hub during the extraction process.
For a fuller understanding of the nature of the present invention, reference is made to the following detailed description taken in connection with the drawings.